Hello, first of all, investigation is needed to determine the cause of your cough. I ll mention a few possibilities: - bronchial asthma, which is usually accompanied by wheezing, may awake you at night and feel tightness in the chest - allergy, despite the negative tests, particularly if you ve also had rhinitis and conjunctivitis. - respiratory tract infections, which are very common in the cold season and can be transmitted to you from infected individuals, particularly if you work or come into contact with many people (including young children). - sinusitis, commonly accompanied by headache. The list limited to the most common causes. Your doctor should determine the cause by clinical examination and perhaps radiological and/or laboratory testing. I hope I ve helped! You can contact me again, if you d like more information. Kind Regards!